merge revision(s) 40791,40806: [Backport #8424]

	* eval_intern.h (TH_PUSH_TAG): ensure jmpbuf to be accessible before
	  pushing tag to get rid of unaccessible tag by stack overflow.

	* vm_core.h (rb_vm_tag): move jmpbuf between tag and prev so ensure to
	  be accessible.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@41054 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 5 insertions, 1 deletions

diff --git a/vm_core.h b/vm_core.h
index 2ac57fc112..0bffdd3daa 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -461,10 +461,14 @@ enum rb_thread_status {
 
 typedef RUBY_JMP_BUF rb_jmpbuf_t;
 
+/*
+  the members which are written in TH_PUSH_TAG() should be placed at
+  the beginning and the end, so that entire region is accessible.
+*/
 struct rb_vm_tag {
-    rb_jmpbuf_t buf;
     VALUE tag;
     VALUE retval;
+    rb_jmpbuf_t buf;
     struct rb_vm_tag *prev;
 };